First of all try to update to phpBB 3.0.4 , that will not resolve it but it is always the best to stay up to date with the latest version of phpBB.
And how do you mean it is not showing?, do you get a blank screen, show it errors or what is happing when you add a file ?

You can just download a new package of phpBB3 ; http://www.phpbb.com/downloads/olympus.php , and upload the /styles/subsilver2/imageset/en/ and /styles/prosilver/imageset/en/ directory , those directory's contains the buttons. Please remember this is not a support forum, for support you need to go t...

Deleting a style is completely different than deleting the template/theme/imageset. You have to remember that other styles can use the same template/theme/imageset, and, IMO, deleting them is rather pointless... Yes, that true, but what about if you install a style to see if it match with your need...

Would there be also some adjustment on the style-system? Like this ; when you deleted for example a style (néé no themes, templates or imageset) but just a style. I call you just install the subsilver2 style, but when you think no i don't like it you deleted it. But on that case the hole style that ...